GB1455456A - Gyratory motion devices - Google Patents

Abstract

1455456 Variable-speed gear; mechanical vibrators R NEDELJKOVITCH 16 Nov 1973 [17 Nov 1972 19 Feb 1973] 53347/73 Headings F2D and F2X A gyratory motion device, Fig. 5, comprises a rotary member, e.g. a shaft, fixed axis X, an axially adjustable gyratory member e.g. an inner cone P, connected at its apex S o by a universal joint to the shaft, and a surrounding base cone B, in which the inner cone P can be rolled, the rolling surfaces of the cones P, B being surfaces of revolution generated by a common circular arc rotated about the coincident axes X of the shaft and base cone B, the centre of curvature Q of the arc being situated on a perpendicular to the axis X from the common apex S o of the cones when in the concident position (full lines). In this position the cones are locked together. By axially adjusting the centre of the universal joint from S o leftwards to S, the inner cone P can incline (dotted position P o ) in the base cone B and is able to roll therein with a gyratory movement, the ratio of which to the reverse speed of the universally jointed shaft depending on the axial position of the cone P. Two applications are described. In the first the inner cone P is driven by the universally jointed shaft and the device is used for generating vibrations at a frequency (up to fifty times input speed), which is the speed of gyration of the inner cone P, and is adjusted by axially adjusting its universal joint. The second application is to a steplessly variable friction gear, in which case gyration is produced by driving the inner cone P in the base cone B by mechanical, fluid or electric input means, and output is taken from the universally jointed shaft. In such a gear, Fig. 7, gyration of an outer cone P 2 , connected by a universal joint J 2 to an output shaft A 2 , is produced by an inner cone P 1 rolled inside the cone P 2 by an input shaft A 1 connected to it by a universal joint J 1 . In Fig. 7 the axial positions S 1 , S 2 of both joints J 1 , J 2 are coincident with the apex S o of the base cone B, so that all rolling surfaces are coincident and both shafts are locked against rotation. By moving the centre S 1 of the joint J 1 to the left, the inner cone P 1 can incline in the outer P 2 and the input shaft A 1 can then gyrate the inner cone in the outer P 2 , which is still held stationary by its coincidence with the base cone B. By also moving the centre S 2 of the joint J 2 to the left the outer cone P 2 can incline in the base cone B, whereby the inner cone P 1 can roll the outer P 2 in the base cone B, thereby driving the output shaft A 2 at speeds increasing from zero in accordance with the leftward movement of the joint centre S 2 , until the outer cone P 2 reaches coincidence with the displaced inner cone P 1 , whereupon the speeds of the input and output shafts A 1 , A 2 synchronize. In Fig. 17, not shown, the joint J 2 is axially fixed and the base cone B axially adjusted. A practical arrangement of this form is rated at 250 HP; output speed zero to 1200 r.p.m.; input speed 1200 r.p.m.; gyratory speed 60,000 r.p.m. In operation centrifugal force on the universally jointed cone produces a large Hertzian contact area substantially along the whole length of the contacting arc, and the contact surfaces may have fine axial serrations. The gyrating cone may be of aluminium alloy, which, in a calculated example, reduces the maximum amplitude of vibration to 31 microns.